Well screen



March l, wsu.

Waff.

Filed May 12. 1925 E. c. wlLsoN WELL SCREEN ffy ff..

"J provided with tine straining Patented Mar. 18, 1930 UNITED ELIHU C. WILSON, OF LOS ANGELES, CALIFORNIA VVELI..l SCREEN Application filed May 12, i925.

This invention has to do with strainers or screens for deep Wells and the like, such screens being generally in the nature of perforated lengths of Well pipe or casing provided in the pipe string at or near the well bottom.

By reason of the perforations provided in the screen lengths and the resulting comparative weakness thereof, it often happens that the screens are collapsed or sheared by the action of otl'set lateral forces as the surrounding earth strata shift. rl`he resulting losses incident to making necessary repairs and replacements are too Well known to those skilled in the art to call for comment here.

It is therefore among the objects of the present invention to provide a well screen which is so constructed that it is capable of effectively resisting the collapsing and shearing forces imposed upon it.

It might be supposed that the natural solution would be merely to use pipe of increased thickness; however such an expedient does not satisfy both for the economic reason that it calls for special pipe and for the reason that it is impracticable to perforate eXtra heavy pipe in the manner iiecef-isaryv to provide efficient screening. The perforations must be relatively fine and in great number. and tools of the requisite size to make perforations cannot be made suiliciently sturdy to withstand usage on eXtra heavy pipe. And furthermore the use of extra heavy pipe necessarily decreases the inside diameter of the pipe that can be put down a given size drill ole.

Therefore to secure the requisite Weight and strength the present invention contemplates the use of a double walled pipe; for instance the screen may be made up of two pipes or sections of pipes, one nested within the other, either or both of whichmay be of standard thickness. These two pipes have registering perforations and preferably the outer pipe is openings while the inner pipe has a comparatively large perforation. While I speak of the two walls as being two pipes, it will be apparent from what is said hereinafter that so far as the invention in this application is concerned it is Serial No. 29,663.

broadly immaterial how the outer Wall is put around the inner wall.

outer wall as a over the inner that the outer wall inner pipe; or in o that the outer ately in place however the outer the inner one,

pipe which will be pipe? yet it will be apparent pipe may aroiind the inner pipe.

it is preferred be tightly nested;

lVhile I describe the slipped strengthen each other in a manner which they would not do if t from the inner wa The following detailed outer wall were spaced ll.

specification and the claims appended to this application are directed double-walled stra Oi the other wall, are ins!` that wall and pre bearing against th particularly to a specific form of iner in which tine straining fenine's in one or the other wall. preferably formed in a plug or button ted in a comparatively la rge opening in ferably held in place by a e other Wall. Other forms of straining openings and other forms of construction for reinforcing and strengthening tie pipe (whether the well strainer claimed in ot which a re in part d Vplicaticn. identified lWell pipe be used as a not) are described and iier co-pending applications ivisional of this present ap- Said (ro-pending applications are as follows: pipe and screen, Serial Number 131.354., filed August 25, 1926: and.

"ifi/'ell pipe and screen, Serial 131,855, tiled August 25,

One of the adv vention that the several ma ke up the screen may seinbly; so that the fine Number 1926.

of the present inparts which go to be formed before asscreening openings antages ma)v be formed by whatever process, tools or iiiachineiaY may larger openings may likewise be 1n made. stron 5i attained the in de di fact the outside d be most anaptable, and the through the two pipe Walls ost easilj,v and economically Another advantage lies in the great wihout either decreasing aineter of the screen or objectionablv increasing the outside diameter.

T in iameter need be no large-i' than that of the colliding covers provided between ad acent l engths oi" ordinary pipe.

" the outside.

in accordance with the invention, shown partin section and part of the outside wall bebroken away to show the inner wall: Fig. 2 is an enlarged section on line 22 of Fig. 1;

Fig. 3 is a front elevation of the screening .-iement shown in Fig. 2;

Fig. 4 is a view similiar to Fig. 2 but showing how the screening button may be inserted in the outer pipe fioni the outside;

Fig. 5 is a view similar to Fig. 4 but showing the button secured in place;

Fig. 6 shows anotliei` type of screening button being inserted into the outer pipe Fig. 7 is a view similar to Fig. 6 but showing the button secured in place; and

Fig. 8 shows how the screening element illustrated in Figs. 2 to 7 of the similar to those inclusive may be inserted in the wail inner pipe and held in position by the overhang of the outer pipe.

lt is usually desirable, though not necessary, that the screening perforations be of larger size at the inside of the screen than at Since the screen en'ibodying this invention is made up of two or more pipes, walls or elements which may be perforated before assembly, it is a matter of ease to secure the desired eliect of vari-diameter perforations by properly proportioning the holes in the several elements of the screen, in addition to making the holes iii the outer element narrower or of smaller diameter at their outside than at their inside.

lVhile the screen will first be described as being made up of a plurality of end to end outer pipes on a single inner pipe, it will be understood that it lies within the scope of the invention to space the outer pipes apart or to provide a single outer pipe extending over the entire perforated parts of the inner pipe.

In Figs. 1 and 2 numerals 10, ltrL and 10b designate lengths of inner pipes secured together by coupling collars 11 in the usual manner. Before the outer casing 12 is aflixed thereto the pipes 10 are punched or drilled to provide relatively large perforations 13. The outer pipes or casings 12 may be made up of a single length between collars 11 or of several lengths abutting endwise against each other and abutting collars 11 endwise. These several lengths or sections 12 may be, if desired, butt-welded together at their ends and furthermore they may be welded to collars 11 if desired. They may preferably be tightly fitted upon inner pipe 10 b v being shrunk upon that pipe g or, as I have indicated before, the sections 12 may be actually formed around pipe 10 by bending the sheet of which the sections 12 are made up and then welding the seam (see 12a in Fig. 1) and thereby forming the outei pipe wall. And if desired the sections 12 may loe spot-welded to the inner pipe at various points.

Putting the outer pipe 12 on in short sections facilitates the shrinking operations, as will be well understood but when the sections are then welded end to end they become in eiiiect a single length extending between collars 11.

The outer pipe 12 is also perforated with perforations 14 before it is put in place upon the inner pipe. As shown at Fig. 2 these perforations 14 a re of large diameter like perforations 1S of the inner pipe, and as shown in that figure the perforation or bore 14 tapers towards the outside; so that the conical or tapering button 1T may be fitted into tapered bore 14 from the inside of pipe 12 and then when pipe 12 is placed upon pipe 1() the button will seat at 20 on the outer face of pipe 1t) where that face of the inner pipe overhangs the larger end of opening 14 in the outer pipe. These straining buttons may have straining apertures of any shape or size desired. For i nce as shown in Fig. 3 they may be in the iorin of narrow slots 18.

the outer pipe or wall is made of several sections as illustrated in Fig. 1 and the several sections are welded end to end o r also welded to collars 11, it will be seen that a complete double walled assembly of the maximum strength is provided, to resist shearing, torsional or crushing forces. However, it may not be desired in all cases to weld the sections endwise to each other or to the collars. For instance, if the sections are shrunk onto the inner pipe and are not welded together, then it is comparatively easy to remove the section of the outer pipe for replacement in case the straining openings become worn through usage. However, in the particular forms of straining elements shown in Figs. 4 and following, it is not necessary to remove the outer pipe in order to remove the straining elements, as such straining elements are insei'table from the outside and may also be removed from the outside.

r"he constructions herein described have especial advantages in that the outer casing or pipe perforations are of relatively large size and of a nature easily formed and insertahle; the screening elements are easily made up in large quantities in the forni of casings or by automatic machine operations; and being capable of being made by special machinery they may have any desired type or number of screening apertures.

lt lies within the scope of the invention to retain the buttons in place by means other los '3 and than those shown and described herein, but the means here illustrated are preferable in that they dispense with independent holding means and call for the minimum number of operations to prepare the various elements for assembly. Thus in Figs. 4 and following where the screening elements or buttons are shown as insertable and removable from the outside of the outer pipe, the buttons are still held in place by shouldering upon the inner pipe, the buttons being held from inward displacement by the inner pipe and from outward displacement by the formation of the outer pipe now about to be described.

In Fig. 4, outer pipe perforations 14e are or' a diameter, throughout, to take the base of conical buttons 17e. After the buttons are inserted the metal around the mouths of perforations 14e are peened or swedged as at lei in Fig. 5 to hold the buttons from displaceme nt outwardly.

In Fig. 6 perforation Mf is of substantially the same configuration as lila in Fig. while button lf is bowed to such an extent that its 1 fnaior base may be inserted through the restricted mouth of aperture lef. lVhen this base is seated on the overhanging portion f of the inner pipe, as shown in dotted lines, the exposed end of the button is struck inwardly, Jhus expanding the button behind the overl; g 14, illustrated in Fig. 7.

I 1g. 8 illustrates how screening elements. similar to the buttons previously described, may be inserted in the walls of the inner pipe heid from displacement bythe outer pipe. (loi. .cal bul'ninr- 14g are lield from inward llispiacemen by reason of the taper of r i'for tions 13g in pipe lOg, while the porion of outer pipe lQg that define perforations irl. overhanfrs the base of the button to hold it from ouiward displacement. The button may be inserted in fperture lg before the outer pipe is applied., or, by properly proportioning the button, it may be initially bowed. as Fig. (i. slipped through perforation 14g after the outer pipe is on the inner and then spread o bring its base behind portion lf Inst as the lnutons of Figs. 4-7 may be inserted from the outside, it will be understood they ran be withdrawn to the outsi le. In Fig. 5 the peen at 14 maybe worked up. or in Fig. 7 the button may be bowed up to its original shape (Fig. nd in removing worn buttons it will be understood that mutilation ofthe buttons is no objection.

It will be understood the drawings and des-cription are intended only to illustrate the invention and not to limit it.

I claim:

l. In a well screen embodying a double wall casing, the two walls having registering pertorations, screening elements in the perforaions of the outer wall, means on the outer rfll adapted to prevent outward displacement ofthe elements. and the inner wall being adapted to prevent inward displacement of the elements.

2. In a well screen embodying a double wall casing, the two walls having registering perforations, screening elements in the perforations of the outer wall, means on the outer wall adapted to prevent outward displacement of the elements, and the inner wall having portions overhanging the outer wall perforations in a manner to prevent. inward displacement of said elements.

il. In a well screen embodying a double wall casing, the two walls having registering perforations, screening elements in the perforations of one wall, and means on said one wall adapted to prevent displacement of the elements in one direction, the other wall being adapted to eoaet with the elements in a manner to prevent their displacement in the opposite direction.

t. In a well screen embodying a double walled pipe, the two walls having registering openings, the opening in one wall being larger han the opening in the other so that a shoulder is presented at the surface of the second mend ioned wall, a screening element set in the opening of the iirst mentioned wall and shouldering against said shoulder.

5. In a well screen embodying a double waited pipe, the two walls having registering openings, the opening in one wall being larger than the opening in the other so that a shoulder is presented at the surface of the second i ienioned wall, a screening element set in the er zoning of the first mentioned wall and shouldering against said shoulder, the opening in the lirst mentioned wall being larger at the end adjacent the second mentioned wall and said shoulder than it is at its other end, and the screening element fitting said opening being thereby prevented from displacement.

6. In a well screen embodying a double walled casing, the two walls having registering openings, the opening in the outer wall being larger than that in the inner wall and being substantially conical with its larger end next to the inner wall, so that the inner wall presents a shoulder at the larger end of the opening in the outer wall, and a substantially cone shaped strainer button set in the conical opening in the outer wall and shouldering against said shoulder presented by the inner wall.

In witness that I claim the foregoing I have hereunto subscribed my name this 16 day of April, 1925.

ELII-III C. WILSON. 

